A. Field of the Invention
This invention relates to a classifier or a conveying and stacking system for transporting sheets of material and stacking or classifying the sheets into separate piles. More particularly, the present invention describes a conveying and stacking system which utilizes a pivotal conveyor having a means for forcing air onto sheets of material being conveyed when the pivotal conveyor is arranged in a position so that it may not further convey the sheets. The sheets are forced downwardly onto a further conveyor after being struck by the air jets. The sheets are then transported to a stacking means.
The present invention also utilizes a conveyor which is located downstream from the pivotal conveyor and which also employs air jet means for forcing sheets of material onto another conveyor which transports the sheets onto another stacking means.
B. Background of the Invention
Article conveying systems are well known in the prior art, and a typical example is disclosed in U.S. Pat. No. 3,339,705. Here, there is set forth a device for conveying articles which utilizes two conveyor belts through which an item is transported. The items are engaged by resilient impellers which extend radially outward from a roller so that the impellers contact the items and urge them towards an intercepting member. The items are then dropped downwardly onto another conveyor belt which transports the items to a succeeding processing device. U.S. Pat. No. 3,339,705 does not disclose a conveying system which will transport sheets of material at a relatively high rate of speed and then force the material onto another conveyor by means of air jets whereupon the sheets will be stacked upon a weight responsive stacking means. The present invention provides these features and is therefore a significant step ahead in the article conveying art.
Another stacker apparatus of relevance is disclosed in U.S. Pat. No. 3,729,188, wherein a stacking apparatus stacks documents at very high speeds. The documents are transported to a stacking bin by a belt transport system, the documents being continuously in contact with the belt. As the document approaches the stacking bin, a roller adjacent thereto forces the trailing edge of the document downward onto the stack. While U.S. Pat. No. 3,729,188 is satisfactory for stacking documents, it does not employ the novel features of the present invention. The handling of sheets of metallic material transported at a high rate requires a means for forcing the sheets downwardly onto another conveyor for high speed stacking.
In U.S. Pat. No. 3,608,695 there is disclosed a conveyor assembly for pieces of lumber for obtaining a uniform flow rate of the pieces so they may be arrested and then permitted to arrive at a pre-determined position with respect to the lugs of a high speed conveyor. The pieces or boards are then released one board at a time at predetermined time intervals. U.S. Pat. No. 3,603,695 does not set forth a system for stacking sheets of material at high rates of speed using the pivotal conveyor having air jet means of the present invention.
A method for automatically stacking lightweight plastic articles being ejected from plastic shaping equipment which involves air conveying the article as disclosed in U.S. Pat. No. 3,685,671. In this patent, plastic articles which are ejected from plastic shaping equipment are conveyed by air jets and then turned by air jets into a stack of trays which are accumulated within a container. U.S. Pat. No. 3,685,671 further discloses dual friction wheels aligned opposite each other on the discharge end of the duct leading to the container. Means for rotating the friction wheels at a constant speed to stack the articles is also provided. This patent does not disclose a pivotal conveying means having air jets used in conjunction with another conveyor having air jets to form two stacks of material.